This invention relates to the repair of flat roofs. Typically formed as a built-up composite of one or more of the following materials: asphalt, roofing paper, felt, rubber, plastic, fiberglass, gravel and insulation, these roofs may vary. in thickness from xc2xd inch to more than 2 feet thick. In the thickest of these roofs, much of their bulk is associated with multiple layers of insulation.
Whenever a flat roof needs to be replacedxe2x80x94whether because of wear or other physical damage, one must usually remove the old roof from the roof deck first. But removing it is the most labor intensive part of a conventional roofing job. Since the manual removal of old roofing material is such a strenuous, back-breaking job, it has been hard to find good workers willing to do this type of work for any extended period of time. Exacerbating this situation has been the fact that the longer a job takes the more likelihood there is it will rain, making time of the essence in completing any roofing project. Roofing contractors have long sought a way to save both on labor cost and on the time required to complete a roofing job.
The primary object of this invention is to provide an easy-to-use, self-propelled machine of small turning radius, which can be used to scrape off old roofing material from a roof deck and then transfer this material, in one continuous operation and without manually handling it, to an open cart. The cart, which may be of the type commonly used by roofers, is then moved to the edge of the roof and dumped, preferably directly into the bed of a truck parked near the building.
In accordance with the present invention, there is provided a machine which comprises a frame, a pair of wheels rotatably connected to the frame, a chute, an inclined flat conveyor belt movably mounted thereon, a short ramp, and a lower front member having a chisel-like front edge and a generally flat upper surface. Rigidly attached to the front member, the ramp extends rearwardly over the lower end of the conveyor belt.
In the lower front member, the flat upper surface, which extends rearwardly of the chisel-like front edge, is disposed generally horizontally and at slightly less of an incline than the front edge itself. In use, the entire lower front member is employed as a wedge. Instead of being used in a scraping action to remove old roofing, the lower front member is forced, for a considerable distance, between the old roofing material and a roof deck, thereby prying loose roofing in the process.
By so wedging the lower front member between the roof and the roof deck and then driving the machine forward, one can utilize it to pry large pieces of roofing material free of the roof deck. Moreover, the action of the lower front member, whereby nails are pried out rather than being sheared off, enables this improved machine to remove large pieces of roofing even in situations in which it is heavily nailed. For ease of operation, it is recommended that a roof which is about to be removed be scored into squares, each of which has a width which is less than that of the conveyor belt. Preferably, the squares measure about 3 feet by 3 feet.
As the machine moves forward, loosened roofing material slides across the short ramp and onto the flat conveyor belt. The conveyor then moves the squares of the old roofing material upwardly and away from the cutting edge of the chisel-like front member. At the distal end of the conveyor belt, this material is transferred to a chute which is directly downwardly and, from it, falls under the force of gravity into an open cart. In the preferred embodiment, the cart is drawn by the machine as it being loaded. When the cart has been filled, it is moved to the edge of the roof for emptying; and another cart is positioned under the discharge chute of the machine.
The machine further comprises means, including a pair of control levers with handles, for controlling the motion of the wheeled frame. In use, an operator walks behind and to one side of the machine. From this vantage point, he can observe the action of the chisel-like front member as its cutting edge enters into the roofing material, as well as the movement of old roofing material up the conveyor and into the cart. He can also control the machine by suitably manipulating the control levers. Forward motion of the machine is achieved by pushing both handles forward. The harder the push, the greater the speed. And, if the operator pulls both handles backward, the machine goes into reverse. To turn the machine, the operator pushes on the handle furthest from the side in the direction he wishes to turn and pulls the other handle; to turn in the opposite direction, he reverses this operation, pulling the handle which had been pushed and vice versa. In an alternate embodiment, means for controlling the motion of the wheeled frame comprises a joy stick control.
The machine still further includes a hydraulic power system having a hydraulic pump, an engine for driving this pump, a hydrostatic transmission, and two sets of hydraulic motors. The hydraulic power system insures that the machine operates reliably even under the extremely dusty conditions produced when old roofing material is dislodged and dropped into a cart. One of these sets of hydraulic motors is used to drive the wheels which support the frame. Operated independently of each other, the two hydraulic motors linked to this pair of drive wheels give the machine maximum traction and flexibility of operation. Another set of hydraulic motors is used to move the conveyor belt.
In an alternate embodiment, an electric motor, instead of an engine, is used to drive the hydraulic pump. Switching from an engine to an electric motor can be readily accomplished with this machine by connecting the power unit to the hydraulic pump.
In another alternate embodiment, the engine is mounted above the conveyor belt on a bracket attached to the wheeled frame, with the engine being mounted in such a way as to both lower the amount of roof dust impinging on the engine and keep more weight above the chisel-like front member of the machine.
A modification of the machine which includes means for adjusting the angle at which the conveyor belt is held relative to the surface of the roof is under development. Experience has shown that the optimum setting for this angle varies from 15 to 60 degrees, depending upon the type of roofing material.